This description relates to filtering for detection of limited-duration distortion.
Various signal processing techniques can be used for noise reduction of signals that may have been distorted in certain ways due to noise sources. In some cases, the distortion corresponds to additive noise, such that an undesired noise signal is added to a desired signal to produce a signal that may still resemble the desired signal but has certain distortions caused by the added noise signal. When the noise signal has characteristics that enable it to be distinguished from the desired signal, certain techniques can be applied to reduce the distortions. For example, if the noise signal has a frequency spectrum that is concentrated in a frequency range that is higher or lower than the frequency spectrum of the desired signal, frequency filtering (e.g., high-pass or low-pass filtering) can be used to reduce the amplitude of the noise components of the distorted signal without substantially reducing the amplitude of the desired components of the distorted signal. In some cases, the distortion is linear, such that a linear filter (e.g., a frequency filter) could be used to reverse the distortion applied to the desired signal (if the characteristics of such a filter were known). Nonlinear distortion typically cannot be completely reversed by application of a linear filter.